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by oftenwrong 4323 days ago
>Hmm... I've used :x to write+quit in Vim for years. And, :X is to encrypt+quit. Don't have a year when that was added though. Could be fun to try and dig that up.

:x (short for :xit) was in the original ex written by Bill Joy in 1976. According to Joy[1], ex pulled together ideas from a few different places:

1. em from QMC, written by George Coulouris[2]

2. a modified version of ed from UCLA

3. An early version of ex written by Charles Haley based on the em source in 1976

4. Bill Joy himself

em uses 'x' for its interactive find-and-replace mode ("exchange"), so it didn't originate there. That leaves 2, 3, and 4 as possible origins. I can't find anything on the UCLA ed. If the origins are in 3 or 4, :x is from 1976.

[1] http://roguelife.org/~fujita/COOKIES/HISTORY/1BSD/exrefm.pdf

[2] http://www.eecs.qmul.ac.uk/~gc/history/